Hard disk drives are used in almost all computer system operations. In fact, most computing systems are not operational without some type of hard disk drive to store the most basic computing information such as the boot operation, the operating system, the applications, and the like. In general, the hard disk drive is a device which may or may not be removable, but without which the computing system will generally not operate.
The basic hard disk drive model was established approximately 50 years ago and resembles a phonograph. That is, the hard drive model includes a hard storage disk that spins at a standard rotational speed. An actuator moves a magnetic read/write head over the disk. The actuator arm carries a head gimbal assembly (HGA) that includes a slider and a suspension with a nose portion for directly contacting a ramp used during the load and unload cycles for a load/unload drive. The slider carries a head assembly that includes a magnetic read/write transducer or head for reading/writing information to or from any desired location on the disk.
In operation, the hard disk is rotated at a set speed via a spindle motor assembly having a central drive hub. Additionally, there are tracks evenly spaced at known intervals across the disk. When a request for a read of a specific portion or track is received, the hard disk aligns the head, via the arm, over the specific track location and the head reads the information from the disk. In the same manner, when a request for a write of a specific portion or track is received, the hard disk aligns the head, via the arm, over the specific track location and the head writes the information to the disk.
Over the years, the disk and the head have undergone great reductions in their size. Much of the refinement has been driven by consumer demand for smaller and more portable hard drives such as those used in personal digital assistants (PDAs), MP3 players, and the like. For example, the original hard disk drive had a disk diameter of 24 inches. Modern hard disk drives are much smaller and include disk diameters 3.5 to 1 inches (and even smaller 0.8 inch). Advances in magnetic recording are also primary reasons for the reduction in size.
However, as the size of hard disk drives are reduced, the methods used for assembling the components within the hard disk drive and attaching components of the hard disk drive are quickly reaching there design limitations. For example, the suspension portion of the head gimbal assembly is stainless steel while the arm is aluminum. Presently, these dissimilar metals, e.g., the arm and suspension, are swaged together due to the inability of welding dissimilar metals. However, because of the overall reduction in component size, the swaging is no longer as reliable as it was when the components were bigger and more surface area was available. In some cases, the swaging of the smaller components results in distortions to the mount plate resulting in deleterious gram loading and static attitude changes at the head. Moreover, the dynamic flutter is also increased.
Solutions to the swaging issue brought on by component size reduction include adhesive bonding or modification of component make-up such as forming the arm from stainless steel. However, adhesive bonding is not re-workable and if it is incorrectly applied the parts are no longer usable and must be scrapped. This is an expensive solution. Additionally, the formation of the components from different materials, e.g., an aluminum arm, significantly degrades dynamic performance of the components.